1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include "opt_inet.h"
30#include "opt_inet6.h"
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/mbuf.h>
37#include <sys/malloc.h>
38#include <sys/ctype.h>
39#include <sys/errno.h>
40#include <sys/rwlock.h>
41#include <sys/socket.h>
42#include <sys/syslog.h>
43
44#include <net/if.h>
45#include <net/if_var.h>
46
47#include <netinet/in.h>
48#include <netinet/in_systm.h>
49#include <netinet/in_var.h>
50#include <netinet/ip_var.h>
51#include <netinet/ip_fw.h>
52#include <netinet/ip.h>
53#include <netinet/ip6.h>
54#include <netinet6/ip6_var.h>
55
56#include <netpfil/ipfw/ip_fw_private.h>
57
58#include <netgraph/ng_message.h>
59#include <netgraph/ng_parse.h>
60#include <netgraph/ng_ipfw.h>
61#include <netgraph/netgraph.h>
62
63static int		ng_ipfw_mod_event(module_t mod, int event, void *data);
64static ng_constructor_t	ng_ipfw_constructor;
65static ng_shutdown_t	ng_ipfw_shutdown;
66static ng_newhook_t	ng_ipfw_newhook;
67static ng_connect_t	ng_ipfw_connect;
68static ng_findhook_t	ng_ipfw_findhook;
69static ng_rcvdata_t	ng_ipfw_rcvdata;
70static ng_disconnect_t	ng_ipfw_disconnect;
71
72static hook_p		ng_ipfw_findhook1(node_p, uint32_t );
73static int	ng_ipfw_input(struct mbuf **, struct ip_fw_args *, bool);
74
75/* We have only one node */
76static node_p	fw_node;
77
78/* Netgraph node type descriptor */
79static struct ng_type ng_ipfw_typestruct = {
80	.version =	NG_ABI_VERSION,
81	.name =		NG_IPFW_NODE_TYPE,
82	.mod_event =	ng_ipfw_mod_event,
83	.constructor =	ng_ipfw_constructor,
84	.shutdown =	ng_ipfw_shutdown,
85	.newhook =	ng_ipfw_newhook,
86	.connect =	ng_ipfw_connect,
87	.findhook =	ng_ipfw_findhook,
88	.rcvdata =	ng_ipfw_rcvdata,
89	.disconnect =	ng_ipfw_disconnect,
90};
91NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
92MODULE_DEPEND(ng_ipfw, ipfw, 3, 3, 3);
93
94/* Information we store for each hook */
95struct ng_ipfw_hook_priv {
96        hook_p		hook;
97	uint32_t	cookie;
98};
99typedef struct ng_ipfw_hook_priv *hpriv_p;
100
101static int
102ng_ipfw_mod_event(module_t mod, int event, void *data)
103{
104	int error = 0;
105
106	switch (event) {
107	case MOD_LOAD:
108
109		if (ng_ipfw_input_p != NULL) {
110			error = EEXIST;
111			break;
112		}
113
114		/* Setup node without any private data */
115		if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
116		    != 0) {
117			log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
118                	break;
119		}
120
121		/* Try to name node */
122		if (ng_name_node(fw_node, "ipfw") != 0)
123			log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
124			    __func__);
125
126		/* Register hook */
127		ng_ipfw_input_p = ng_ipfw_input;
128		break;
129
130	case MOD_UNLOAD:
131		 /*
132		  * This won't happen if a node exists.
133		  * ng_ipfw_input_p is already cleared.
134		  */
135		break;
136
137	default:
138		error = EOPNOTSUPP;
139		break;
140	}
141
142	return (error);
143}
144
145static int
146ng_ipfw_constructor(node_p node)
147{
148	return (EINVAL);	/* Only one node */
149}
150
151static int
152ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
153{
154	hpriv_p	hpriv;
155	uint32_t cookie;
156	const char *cp;
157	char *endptr;
158
159	/* Protect from leading zero */
160	if (name[0] == '0' && name[1] != '\0')
161		return (EINVAL);
162
163	/* Check that name contains only digits */
164	for (cp = name; *cp != '\0'; cp++)
165		if (!isdigit(*cp))
166			return (EINVAL);
167
168	/* Convert it to integer */
169	cookie = (uint32_t)strtoul(name, &endptr, 10);
170	if (*endptr != '\0')
171		return (EINVAL);
172
173	/* Allocate memory for this hook's private data */
174	hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
175	if (hpriv== NULL)
176		return (ENOMEM);
177
178	hpriv->hook = hook;
179	hpriv->cookie = cookie;
180
181	NG_HOOK_SET_PRIVATE(hook, hpriv);
182
183	return(0);
184}
185
186/*
187 * Set hooks into queueing mode, to avoid recursion between
188 * netgraph layer and ip_{input,output}.
189 */
190static int
191ng_ipfw_connect(hook_p hook)
192{
193	NG_HOOK_FORCE_QUEUE(hook);
194	return (0);
195}
196
197/* Look up hook by name */
198static hook_p
199ng_ipfw_findhook(node_p node, const char *name)
200{
201	uint32_t n;	/* numeric representation of hook */
202	char *endptr;
203
204	n = (uint32_t)strtoul(name, &endptr, 10);
205	if (*endptr != '\0')
206		return NULL;
207	return ng_ipfw_findhook1(node, n);
208}
209
210/* Look up hook by rule number */
211static hook_p
212ng_ipfw_findhook1(node_p node, uint32_t cookie)
213{
214	hook_p	hook;
215	hpriv_p	hpriv;
216
217	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
218		hpriv = NG_HOOK_PRIVATE(hook);
219		if (NG_HOOK_IS_VALID(hook) && (hpriv->cookie == cookie))
220                        return (hook);
221	}
222
223	return (NULL);
224}
225
226static int
227ng_ipfw_rcvdata(hook_p hook, item_p item)
228{
229	struct m_tag *tag;
230	struct ipfw_rule_ref *r;
231	struct mbuf *m;
232	struct ip *ip;
233
234	NGI_GET_M(item, m);
235	NG_FREE_ITEM(item);
236
237	tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
238	if (tag == NULL) {
239		NG_FREE_M(m);
240		return (EINVAL);	/* XXX: find smth better */
241	}
242
243	if (m->m_len < sizeof(struct ip) &&
244	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
245		return (ENOBUFS);
246
247	ip = mtod(m, struct ip *);
248
249	r = (struct ipfw_rule_ref *)(tag + 1);
250	if (r->info & IPFW_INFO_IN) {
251		switch (ip->ip_v) {
252#ifdef INET
253		case IPVERSION:
254			ip_input(m);
255			return (0);
256#endif
257#ifdef INET6
258		case IPV6_VERSION >> 4:
259			ip6_input(m);
260			return (0);
261#endif
262		}
263	} else {
264		switch (ip->ip_v) {
265#ifdef INET
266		case IPVERSION:
267			return (ip_output(m, NULL, NULL, IP_FORWARDING,
268			    NULL, NULL));
269#endif
270#ifdef INET6
271		case IPV6_VERSION >> 4:
272			return (ip6_output(m, NULL, NULL, 0, NULL,
273			    NULL, NULL));
274#endif
275		}
276	}
277
278	/* unknown IP protocol version */
279	NG_FREE_M(m);
280	return (EPROTONOSUPPORT);
281}
282
283static int
284ng_ipfw_input(struct mbuf **m0, struct ip_fw_args *fwa, bool tee)
285{
286	struct mbuf *m;
287	hook_p	hook;
288	int error = 0;
289
290	/*
291	 * Node must be loaded and corresponding hook must be present.
292	 */
293	if (fw_node == NULL ||
294	   (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL)
295		return (ESRCH);		/* no hook associated with this rule */
296
297	/*
298	 * We have two modes: in normal mode we add a tag to packet, which is
299	 * important to return packet back to IP stack. In tee mode we make
300	 * a copy of a packet and forward it into netgraph without a tag.
301	 */
302	if (tee == false) {
303		struct m_tag *tag;
304		struct ipfw_rule_ref *r;
305		m = *m0;
306		*m0 = NULL;	/* it belongs now to netgraph */
307
308		tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r),
309			M_NOWAIT|M_ZERO);
310		if (tag == NULL) {
311			m_freem(m);
312			return (ENOMEM);
313		}
314		r = (struct ipfw_rule_ref *)(tag + 1);
315		*r = fwa->rule;
316		r->info &= IPFW_ONEPASS;  /* keep this info */
317		r->info |= (fwa->flags & IPFW_ARGS_IN) ?
318		    IPFW_INFO_IN : IPFW_INFO_OUT;
319		m_tag_prepend(m, tag);
320
321	} else
322		if ((m = m_dup(*m0, M_NOWAIT)) == NULL)
323			return (ENOMEM);	/* which is ignored */
324
325	if (m->m_len < sizeof(struct ip) &&
326	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
327		return (EINVAL);
328
329	NG_SEND_DATA_ONLY(error, hook, m);
330
331	return (error);
332}
333
334static int
335ng_ipfw_shutdown(node_p node)
336{
337
338	/*
339	 * After our single node has been removed,
340	 * the only thing that can be done is
341	 * 'kldunload ng_ipfw.ko'
342	 */
343	ng_ipfw_input_p = NULL;
344	NG_NODE_UNREF(node);
345	return (0);
346}
347
348static int
349ng_ipfw_disconnect(hook_p hook)
350{
351	const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
352
353	free(hpriv, M_NETGRAPH);
354	NG_HOOK_SET_PRIVATE(hook, NULL);
355
356	return (0);
357}
358